One Tag Worldwide!
SAW RFID READER SYSTEM
Model 501
USER’S MANUAL
Published: October, 2004
Part Number: 415-0001-001 rev B
RF SAW, Inc.
900 Alpha Drive – Suite 400
Richardson, TX
Telephone: (469) 916-5950
Fax: (469) 916-5951
http://www.rfsaw.com
Notices
Changes or modifications to this device not expressly approved by
the manufacturer could void the user’s authority to operate the
equipment.
To reduce potential radio interference to other users, the antenna type
and its gain should be so chosen that the equivalent isotropically
radiated power (EIRP) is not more than that required for successful
communication
The installer of the radio equipment must ensure that the antenna is
located or pointed such that it does not emit RF field in excess of the
Health Canada limits for the general population; consult Safety Code 6
obtainable from Health Canada’s website www.hc-sc.gc.ca/rpb.
Note: This equipment has been tested and found to comply with the
limits for a Class A digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against
harmful interference when the equipment is operate in a commercial
environment. This equipment generates, uses, and can radiate radio
frequency energy and , if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio
communications. Operations of the equipment in a residential area is
likely to cause harmful interference in which case the user will required
to correct the interference at his own expense.
Copyright and Trademarks
Copyright 2004 RF SAW, Inc. All rights reserved.
This document is protected by copyright with all rights reserved. No
part of the document may be reproduced or transmitted by any means
or in any form without prior consent in writing from RF SAW, Inc.
Limited Warranty
RF SAW, Inc. warrants its products to the original purchaser to be free
of material or workmanship defects for a period of 90 days from date of
purchase. RF SAW, Inc. will repair or replace the defective product at
their discretion.
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 2
The information in this document is subject to change without notice.
RF SAW, Inc. shall not be liable for errors contained herein or for
incidental or consequential damages in connection with furnishing,
performance, or use of this material.
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 3
TABLE OF CONTENTS
Section 1 – INTRODUCTION …………………………………... 5
1.1 Product Description……………………………………………… 5
1.2 System Technology……………………………………………… 5
1.3 System Features………………………………………………….. 5
1.4 Operational Description………………………………………… 6
1.5 System Components…………………………………………….. 10
Section 2 – SPECIFICATIONS………………………..………... 11
2.1 System………………………………………………………………. 11
2.2 Reader………………………………………………………………. 11
2.3 Serial Communications Interface……………………………. 11
Section 3 – INSTALLATION…………………………………….. 13
3.1 General Installation……………………………………………… 13
3.2 Single Antenna Installation……………………………………. 13
3.3 Dual Antenna Installations…………………………………….. 13
3.4 Reader Installation………………………………………………. 14
Section 4 – TROUBLESHOOTING……………………………… 16
Section 5 – ACRONYMS and ABBREVIATIONS……………. 17
Section 6 – CONTACT US……………………………………….. 18
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 4
SECTION 1 – INTRODUCTION
1.1 Product Description
The Model 501 SAW RFID Reader System incorporates patented radio frequency
identification technology to provide a compact, low power, RFID solution utilizing
Surface Acoustic Wave (SAW) technology to achieve superior performance in
passive–tag RFID.
The Model 501 SAW RFID Reader System supports global 2.45 GHz operation,
and offers superior long–range reading capability with high–speed and accuracy
over a wide temperature range. The system provides a wide range of antenna
configurations and data capacities in the tag devices to match the specific needs
of an RFID application.
1.2 System Technology
The Global SAW Tag (GST) is a breakthrough application of the proven SAW
technology that is widely used in cell phones and other mass market products.
Surface Acoustic Wave (SAW) tags are truly passive devices in which the
piezoelectric effect allows direct RF interrogation of an encoded, sub–micron
reflector pattern without external power. SAW tags avoid the inherent
performance limitations of IC chip–based products that must obtain DC power
from large continuous RF reader signals. Thus, SAW RFID tags read robustly
even if reader signal strength is low or is temporarily interrupted (as often
happens in the real world). This translates into superior read range and signal
penetration.
In addition, SAW tags use interference–resistant broadband signals. A SAW tag
reader is inherently capable of determining the tag’s range, speed, direction of
travel and temperature.
RF SAW, Inc’s family of SAW tags, readers, and antennas allow flexible systems
to be customized for a wide range of military, industrial and commercial
applications. The inherent advantages of GST technology offer users the
preferred RFID solution.
1.3 System Features
• Worldwide 2.45 GHz tags
• More than 128 bits of address space
• 96- and 64-bit tags: EPC alternative technology compatible
• Compact, low power reader
• High performance GST tags
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 5
• Solution for difficult reading environments (liquids and metals)
• Superior read range
• Robust anti–collision
• High speed, accurate reading
• Interference resistant
1.4 Operational Description
The SAW RFID Reader System Model 501 and the RF SAW, Inc. family of Global
SAW Tag (GST) products are the key elements of a new Radio Frequency
Identification (RFID) system that is characterized by low power operation and
high read range. Surface Acoustic Wave (SAW) devices are widely used in many
products such as cell phones and other mass market products. SAWs have also
been used as tag devices in commercial systems but until recently, their
widespread use was not possible due to the limited number of unique codes that
could be produced in these devices. The invention of the Global SAW Tag now
makes it possible to encode SAW devices with data capacities of more than 128
bits. The SAW RFID Reader System Model 501 is designed to be a compact and
cost effective reader for the GST family of RFID tags.
To understand the operation of the system, it is important to review the
operation of SAW devices as they are applied to tag applications.
SAW-based RFID Technology
As shown in Figure 1, the operating principle of a SAW RFID tag is based on
converting an interrogating radio wave from the reader directly into a nano-scale
surface acoustic wave on the SAW chip surface. The tag's antenna is directly
connected to the IDT (interdigital transducer) which uses the piezoelectric effect
in the lithium niobate substrate material to efficiently convert between radio
waves and surface acoustic waves. That acoustic wave then travels past an
encoded set of wave reflectors which interact to produce a unique acoustic wave
pulse train. These pulses are directly converted into an encoded radio wave reply
signal that is sent back to the reader.
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Figure 1 - SAW RFID Operation: The reader emits a radio wave pulse that is directly converted
into a nanoscale Surface Acoustic Wave on the SAW chip surface by the "IDT" (interdigital
transducer). That acoustic wave travels past a set of wave reflectors to produce uniquely encoded
acoustic wave pulses, which travel back to the IDT. The IDT converts those pulses into an encoded
radio wave reply signal that is sent back to the reader. The SAW chip operates using the
piezoelectric effect and does not require DC power. (Note: chip size is not to scale.)
SAW RFID systems are in use today in heavy manufacturing environments.
Previously, these applications were limited to tags with an address range of 14
bits or less. The recent GST breakthrough by RF SAW, Inc. enabled the
development of an encoding algorithm and manufacturing process capable of
producing tags with more than 128 bits of address space. The GST has sufficient
data capacity to comply with EPC encoding and similar global RFID requirements,
which means that SAW-based RFID is now a main-stream high-volume RFID
technology.
The new encoding algorithm uses a limited number of reflectors that encode
data using combinations of pulse time and pulse phase. For example, 16 bits of
data can be encoded with only four pulses spread across 75 tightly spaced time
slots. Six such groups of reflectors provide 96 bits of address space. Additional
groups of overhead data are added for synchronization, error checking, and
simultaneous detection of multiple tags (anti-collision).
A key feature of SAW RFID tags is that they do not use any DC power source.
SAW tags are truly passive devices that operate at any signal level (even very
low) as long as the reply signal received at the reader is sufficient to detect the
data. In high-speed, long-read-range applications, the minimum signal required
at the tag is a fraction of a microwatt. The signal required is even lower in less
demanding situations. Because of this physical characteristic, SAW RFID readers
can use very low transmit power.
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 7
Model 501 SAW RFID Reader System
The Model 501 SAW RFID Reader System operates in the 2.4 to 2.483 GHz ISM
band and can be used in a wide variety of industrial applications. The major
components of the system are the reader, an external power supply that powers
the reader, cables to connect the reader to the antenna system, and a variety of
antenna system configurations that allow the system to be tailored to specific
RFID application. Cabling is also required to connect the reader to a host
computer. A typical system is shown in Figure 2.
Figure 2 - Typical RF SAW, Inc. Model 501 SAW RFID Reader System
Reading of a SAW device can be accomplished with a reader having a wide
variety of signal structures. This is possible because the SAW device itself is a
linear device. Therefore, the signal that is received by the SAW tag is
retransmitted with delays that are determined by the encoding pattern on the
surface of the SAW device itself. One of the methods of reading the tag is to
send a short pulse of RF energy to the tag as described previously. Another
method, often more efficient than the short pulse, uses a swept RF signal in a
technique that is known as FM CW. This technique has been used in radar
systems for many years. This technique minimizes the amount of transmit signal
required for RFID operation and is the technique used in the Model 501 SAW
RFID Reader System. With this technique, the transmitter sweeps across a
relatively wide band of frequencies. Signals received by the receiver from the
tag device are mixed with the sweeping transmit signal producing tones that
correspond to the delay of the returned signals. Measuring the frequency and
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 8
amplitude of these tones allows the delay pattern of a SAW device and its
encoding to be determined by the reader.
In most applications, transmitting the signal to the tag and receiving the
returned signal is done with a single antenna similar to the operation of a radar
system. The size and gain of the antenna is determined by the read range and
directivity that is required to implement a specific RFID application. In some
RFID applications, the reading environment has a considerable amount of signal
attenuation or reflection from the objects being read. A significant improvement
in reading performance can be achieved by using a separate antenna that is
devoted primarily to transmitting the RF signal and a second antenna that is
used primarily to receive the returned tag signal. This configuration allows
reading through the objects instead of the radar mode described above. The
two antenna configuration of the Model 501 SAW RFID Reader System is
implemented with a microwave circulator that is connected to the RF port of the
reader and the two antennas. This configuration is also useful in applications
where there are strong signal reflections or interference in the reading
environment.
To complete the reading function, data from the reader is fed to a host computer
via an RS-485 port. The computer maps the decoded tag information to specific
objects or items that are being identified with the RFID system.
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1.5 System Components
System Item Description RF SAW P/N
READER
Model 501 SAW RFID Reader 411-0001-001
CABLE ASSEMBLIES
Single antenna: 20-ft RG223 412-0001-001
Dual antennas: 2 20-ft RG223 412-0001-001
1-ft RG223 412-0002-001
1 Circulator 412-0003-001
ANTENNA ASSEMBLIES
9 dB gain LCP polarized-HS 414-0001-001
12 dB gain linear polarized-HS 414-0002-001
15 dB gain LCP polarized-HS 414-0003-001
15 dB gain linear polarized-HS 414-0004-001
17 dB gain LCP polarized - HS 414-0005-001
17 dB gain linear polarized-HS 414-0006-001
18 dB gain LCP polarized-HS 414-0007-001
18 dB gain linear polarized-HS 414-0008-001
8 dB gain LCP polarized-HLT 414-0009-001
8 dB gain linear polarized-HLT 414-0010-001
14 dB gain linear polarized-HLT 414-0011-001
15 dB gain linear polarized-HLT 414-0012-001
18 dB gain linear polarized-HLT 414-0013-001
18 dB gain linear polarized-MR 414-0014-001
24 dB gain linear polarized-A 414-0015-001
POWER SUPPLY
120VAC input, 24VDC output 413-0001-001
MANUAL
User’s Manual 415-0001-001
WARNING
Any changes or modifications to the Model 501 SAW RFID System
equipment that are not expressly approved and/or supplied by RF
SAW, Inc. could void the user’s authority to operate the equipment.
This device has been designed to operate with an antenna having a
maximum gain of 24 dB. Antenna having a higher gain is strictly
prohibited per regulations of Industry Canada. The required
impedance is 50 ohms.
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SECTION 2 – SPECIFICATIONS
2.1 System
PARAMETER DESCRIPTION
Tag Element Surface Acoustic Wave (SAW) piezoelectric crystal device
Reader 2.4 GHz ISM band reader
Reader Antennas
Read Range up to 10 meters (depends on system components)
Anti-collision Spatial, and code division implementation
EM Compatibility Adaptive interference filtering
Conventional flat panels (linear and circular polarization)
and parabolas
2.2 Reader
PARAMETER DESCRIPTION
Frequency Range 2.4 - 2.483 GHz
RF Field Strength
RF Port RF – Single Tx/Rx
Data Ports RS-485, DB9 connecter
Tag Read Speed 1000 per second - data collection
50 millivolts per meter maximum ( measured
at 3 meters from antenna)
Dimensions
Weight 2.5 lbs
Power Requirements 18-72 volts DC; 6 watts maximum
Temperature Operating -20° to +50° C
FCC ID SHT005010
9.1” x 6.6” x 2.1” (23.1 cm x 16.8 cm x 5.3
cm)
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 11
2.3 Serial Communication Interface
Electrical Interface Specification
Parameter Description
Signal Format RS-485
Baud Rate 115200 b/s
Data Bits 8
Parity None
Stop Bits 1
Hardware Flow Control None
Maximum Cable Length >1000 ft
Mechanical Interface Specification
Parameter Description
Connector Type DB 9F
Locking Screws 4-40 NF Standoff
Mating Connector DB 9M
Pin Number Assignments
Pin Signal Name
1 T+
2 T3 R+
4 R-
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 12
SECTION 3 – INSTALLATION
3.1 General Installation
a) Unpack the reader system and verify that the reader, antenna(s), RF
cable(s) and power supply are present and that no physical damage has
occurred during shipment. If items are damaged, contact RF SAW, Inc. to
obtain replacement items.
b) Determine the best layout for the major system components. Antennas
must be located within 20 feet of the reader (length of the RF SAW, Inc.
supplied cable P/N 412-0001-001 is 20 feet) and within the read range of
the tagged object to be read. The reader should be located in a dry,
secure location, near a source of power and accessible to data
connections. If a data cable has been provided by RF SAW, Inc., verify
that it is present and that no physical damage has occurred during
shipment. If the data cable is being provided by the user, verify that the
connections are correct by comparing the cable pin assignments to the
Specifications Section of this document.
Note: The antennas used with the Model 501 SAW RFID Reader System are
very directional and proper placement and alignment of the antenna(s) is
needed to achieve the proper tag reading performance of the system.
3.2 Single Antenna Installation
a) Once the reading location has been determined, refer to the instructions
supplied with the antenna to mechanically mount the antenna. A common
method for mounting the antenna is to clamp the antenna mounting
bracket to a metal pipe or similar rigid support that is secured to the floor
or other support structure.
b) Connect the RF cable to the antenna and torque the connector to 8 inch
pounds. Secure the cable to avoid physical damage to the cable during
normal operation. Avoid kinks and sharp bends (less than 2” bend radius)
along the cable as this may damage the cable.
3.3 Dual Antenna Installations
a) Dual antenna configurations are recommended when it is desired to read
tags by reading through the tagged objects or at an angle rather than
reading from one side. If the RF attenuation of the tagged objects is
high, reading performance is improved by mounting the two antennas
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such that they are facing each other or at an angle such that the two
antenna patterns intersect at the tag location on the object.
b) Dual antenna systems make use of a microwave circulator to direct most
of the transmit RF power to one antenna and to direct the received signal
to the reader from the other antenna. The antennas are connected to the
circulator using two of the 20 foot cables (P/N 412-0001-001). In
installations where potential sources of RF interference are known to
exist, the interference can often be minimized or eliminated by purposely
selecting the positions of the transmitting and receiving antennas. The
transmit, receive and reader ports are labeled on the circulator.
Note: Damage can result to the circulator by subjecting the device to high
magnetic fields. Avoid installing the circulator near strong magnets or
other sources of magnetic fields.
c) Connect the RF cables to the antennas and the circulator. Torque the
connector to 8 inch pounds. Secure the cable to avoid physical damage to
the cable during normal operation. Avoid kinks and sharp bends (less
than 2” bend radius) along the cable as this may damage the cable.
3.4 Reader Installation
a) Mount the reader on a shelf or suitable bracket. Connect the antenna to
the antenna port on the reader and torque the connectors to 8 inch
pounds. See Figure 3. Connect the host computer to the reader using
the RS-485 connection on Com Port 1. See Figure 4. If the host
computer does not have an RS-485 interface, install an RS-485 to RS-232
adapter following the instructions supplied with the adapter. When long
data cables are used (> 15 feet), it is recommended to locate the RS-485
adapter at the host computer end of the data cable. A twenty foot cable
with an adapter is available from RF SAW, Inc. and longer cables can be
special ordered. Pin number assignments and electrical interface
specifications can be found in Section 2.3 of this manual.
b) Connect the power supply to the reader using the connector on the front
face of the reader. See Figure 4. Plug the power supply into a 120 volt
ac outlet and verify that the green Power LED on the unit is illuminated.
c) Install the reader interface software on the host computer and start the
software using the user instructions supplied with the software.
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 14
d) Test the system by placing a tag in the read field and verifying that the
tag is read successfully.
Figure 3 – Reader Rear Panel Showing Antenna Connection
Figure 4 – Reader Front Panel Showing Power and Data Connections
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 15
SECTION 4 - TROUBLESHOOTING
Problem Probable Causes Corrective Action
Power LED does not light
Power supply is not connected
to reader
No AC power supplied to
Power Supply
Check plug on front panel of
reader
Check AC voltage to outlet
Reader will not read tags
Reader will not
communicate with host
computer
Degradation in read range
Power Supply is defective Replace Power Supply
Antenna is not connected to
reader
Cable to antenna is defective
Antenna is defective
Tag is defective Try reading known good tags
Communication cables not
connected properly
Communication parameters
are set incorrectly on host
computer
Interference from other 2.4
GHz devices
Check cabling at antenna and
on reader antenna port
Visually inspect cable and
check for continuity with
VOM. Replace if defective
with P/N 412-0001-001 rev A
Visually inspect antenna. If
defective, replace with
identical P/N from RF SAW,
Inc.
Visually inspect cable
connections and correct if
needed
Check parameters in Section
2.3 of this Manual and correct
if necessary
Identify source of interference
and eliminate from reader
input
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 16
SECTION 5 – ACRONYMS and ABBREVIATIONS
ACRONYM DEFINITION
EM Electromagnetic
EPC Electronic Product Code
ERP Effective Radiated Power
FM CW Frequency Modulated Continuous Wave
GST Global SAW Tags
IC Integrated Circuit
ISM band Industrial Scientific and Medical frequency band
RF Radio Frequency
RFID Radio Frequency IDentification
SAW Surface Acoustic Wave
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 17
SECTION 6 - CONTACT US
For sales, services, and technical assistance, please contact us at:
RF SAW, Inc.
900 Alpha Drive
Suite 400
Richardson, TX 75081-6625
USA
Telephone: (469) 916-5950
Fax: (469) 916-5951
Hours of Operation:
Monday – Friday, 8:00 a.m. – 5:00 p.m. CST
Email: info@rfsaw.com
Website: http://www.rfsaw.com/
SAW RFID READER SYSTEM Model 501 - USER’S MANUAL – P/N 415-0001-001 rev A Page 18
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